In the final step of treatment of low level radioactive wastes (LLW) generated in the nuclear power plants, it is generally to make the waste into solid form which is then transported to an intermediate storage site for interim storage, or directly to a final disposal site for final disposal. Solidification is the most important step in the treatment processes, it is to confer upon the wastes long-term chemical and physical stabilities and to offer a higher strength to facilitate transportation and management. Since, solidification process determines the volume of the solidified waste, when the final disposal cost is mainly determined by the volume of the waste form, the over-all cost of the management is consequently again determined principally by the volume efficiency of solidification. Currently, among the solidification methods for LLW, the most frequently used are the three methods of cement solidification, plastic solidification and bitumen solidification, each of the three methods having its own advantages and disadvantages. Generally speaking, the cementitious waste form possesses excellent long-term stability; however, the cement solidification method has a low volume efficiency. On the other hand, while volume efficiency of the plastic solidification method is high and the plastic-solidified waste form possesses a high strength, its long-term stability remains, however, doubtful. Again, in the bitumen solidification method the volume efficiency is high, the strength of the bitumen-solidified waste form is, nevertheless, low and the waste form is also flammable. The current solidifications methods are, therefore, still far from perfection and in many areas need for improvements. Judging from the nature of these solidification methods, the long-term stability of the cement-solidified waste form communicates to the mind of people a very important security in relation to the storage requiring a period of over several hundred years. Hence, it has become a very urgent task to improve the volume efficiency of the cement solidification method in order to reduce the over-all cost in the management of LLW.